Answer:
0.9%
Explanation:
At the instance where you add RBCs to a solution of 0.9% NaCl, they will maintain their shape as well as their size, this is simply to indicate an equilibrium. That entails that the solution is isotonic to the RBCs. This must mean that the concentration of solutes on each side must be equal otherwise osmotic pressure would force water either in or out of the membrane. Therefore, one can also safely assume that RBC's also have a solute concentration of 0.9%.
Answer:
70.77 g/mol is the molar mass of the unknown gas.
Explanation:
Effusion is defined as rate of change of volume with respect to time.
Rate of Effusion=
Effusion rate of oxygen gas after time t = 
Molar mass of oxygen gas = M = 32 g/mol
Effusion rate of unknown gas after time t = 
Molar mass of unknown gas = M'
The rate of diffusion of gas, we use Graham's Law.
This law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows:



M' = 70.77 g/mol
70.77 g/mol is the molar mass of the unknown gas.
I would say the most correct answer is Kilo, as in kilometers. The store would certainly not be milli, or millimeters away from you, would it now? :)
Hope this helps!
Answer:
because they take thousands or even millions of years to naturally replenish or replaced , which is not the average human lifetime